FORT MEADE, Md. (AP) - An Army private charged in the biggest security breach in U.S. history is trying to avoid trial by claiming he was already punished enough when he was locked up alone in a small cell and forced to sleep naked for several nights.

Pfc. Bradley Manning was expected to testify about his treatment during a pretrial hearing set to begin Tuesday and run through Sunday in a military court at Fort Meade.

His lawyers contend Manning was illegally punished by being locked up alone in a small cell for nearly nine months at the Marine Corps brig in Quantico, Va., and having to sleep naked for several nights.

Military judges can dismiss all charges if pretrial punishment is particularly egregious, but that rarely happens. The usual remedy is credit at sentencing for time served, said Lisa M. Windsor, a retired Army colonel and former Army judge advocate now in private practice in Washington.

Manning has also offered to take responsibility for the leak by pleading guilty to reduced charges. The military judge hasn't yet ruled on the offer and prosecutors have not said whether they would still pursue the charges against him.

He was kept at the Marine Corps brig from July 2010 to April 2011 and the military contends the treatment at Quantico was proper, given Manning's classification as a maximum-security detainee who posed a risk of injury to himself or others. He was later moved to Fort Leavenworth, Kan., where he was re-evaluated and given a medium-security classification.

A United Nations investigator called the conditions of Manning's time at Quantico cruel, inhuman and degrading, but stopped short of calling it torture.

The 24-year-old native of Crescent, Okla., faces possible life imprisonment if convicted of aiding the enemy, the most serious of the 22 charges.

He is accused of sending hundreds of thousands of classified Iraq and Afghanistan war logs and more than 250,000 diplomatic cables to the secret-spilling website WikiLeaks while he was working as an intelligence analyst in Baghdad in 2009 and 2010.